Conclusions

The decision whether or not to renew the Diablo Canyon and SONGS operating licenses will have a significant impact on the state’s power supply portfolio and on the communities located near the reactors. Unfortunately, the full implications of this decision are unknown. Even the most straightforward question of how much power would be impacted by this decision cannot be answered with any certainty. While current production levels from the plants are known, it is unclear how performance will change as the plants age—no commercial reactor has yet operated for a full 60 years.

The cost of power from the nuclear plants over the license renewal period will be linked to the performance of the plants. If the plants maintain high levels of performance and safety and do not require significant repairs the costs should remain comparable to current levels with relatively minor increases due to higher nuclear fuel costs and potentially stricter security requirements. However, degradation of major components or extended outages could result in much higher costs. In addition, the plants may be required to retrofit their cooling systems prior to a license renewal. If feasible, this is expected to cost a minimum of $2.6 billion at SONGS and $3.0 billion at Diablo Canyon.

In addition, it is important to consider the environmental impacts from plant operations over an extended 20-year license period, including once-through cooling ocean impacts and impacts from continuing waste accumulation at these plants. The extent of the impacts will depend on the outcomes of state and federal policies and requirements for once-through cooling and on whether a long-term solution to the waste disposal problem is found.

The impact that shutting down one or both of the plants would have on the reliability of California’s electricity grid is unclear at this time. The impact will depend on what other generating and transmission resources are built or retired over the next two decades and on the pattern of population growth in the regions near the plants. This is an area that needs to be investigated further prior to any decision on license renewal.

The loss of the plants would mean the loss of high-paying jobs and tax revenues for the communities located near the reactors. Given current economic conditions, this loss would be felt more strongly in San Luis Obispo County following the closure of Diablo Canyon than it would be in the much larger San Diego and Orange Counties following the closure of SONGS.

Some or all of the loss could be recouped over time by the use of the reclaimed land for other income-generating enterprises or by the development of renewable energy projects elsewhere in the county to replace the nuclear plants. It is also possible that some of the loss could by offset by a rise in property values, if current property values are depressed by the presence of the plants. However, additional study is required to assess whether this is the case and whether the closure of the plants would reverse this impact, especially if nuclear waste remains on-site.